Warp-knit lace strips are conventionally used as border ornament on women's underwear and outerwear. In general, the lace strip is provided with sinuate parts called scallops consisting of repetitive recesses and having protrusions on their edges called picots. The picots are formed of U-bent yarns and protrude from the scallops. Lace fabrics of this type have been knit in a single direction, generally by a Raschel knitting machine and a plurality of units of lace strips have been knit into one piece of fabric extending over the full width of the needle row and have been separated into units in a conventional manner.
In the prior method of separation of the plurality of lace strips into unit strips required cutting a mesh fabric interface between the adjacent lace strips along the sinuate lines of the scallops. This method also required the use of a draw thread yarn to connect picots of adjacent lace strips. The draw thread is pre-knit into the fabric and removed after completion of the knitting to obtain separate units of lace strip.
The described prior method suffers from several disadvantages, i.e., in the separation step. For example, if a manual cutting operation is employed efficiency is low because of the care which must be taken in order to avoid cutting the knitted lace strip. Accurate cutting along a sinuate line is difficult in practical work and yarn ends remain at the cut-end of the mesh fabric. This prevents fine finish of the outer edge of the scallops and clear protrusions of the picots.
Where mechanical cutting is employed, the remaining yarn ends at the outer edge of the scallops are ragged which prevents a fine finish despite any advantages obtained in increased production. Accordingly, it can be seen that lace strips obtained by these methods have been extremely low in commercial value as border ornaments.
When a draw thread is employed, separation in units by release of the draw thread is better than the use of cutters, however, other disadvantages are present in the inferior ornamental properties since the draw thread is knitted in from the sinuate scallops to the protruding scallops. Since alignment of protruding ends of the picots of the adjacent lace strip is required, this causes sinuation of the scallops on one lace strip to be weaker and nearly straight at the protrusion of the scallops of the adjacent lace strip, and picots cannot be provided on the adjacent lace strip.
Illustrative of the known prior patent art on separating strips of fabric from a knitted fabric by dissolving soluble thread are U.S. Pat. Nos. 289,094 and 307,801. These patents disclose the use of soluble threads to separate strips of fabrics where the soluble threads are woven or knitted into the ground fabric.